Magnum Energy MS2812

Last updated: October 24, 2026

Magnum Energy MS2812
3.5/5#22 of 41 in inverter-chargers 12V inverters
3.5

For full-time RVers who want a rugged low-frequency inverter-charger that will start air conditioners and charge fast from a generator.

  • 2,800 WContinuous
  • 3,900 WSurge
  • 2.5 AIdle draw
  • YesUL listed
  • 3 yearsWarranty
See it at Magnum Energy

No store we check sells it online; the maker lists where to buy or who installs it.

Pros
  • Low-frequency transformer handles big motor starts for minutes, not milliseconds
  • Fast 125 A PFC charger is easy on generators
  • ETL listed to UL 458; built for RV and fire-truck duty
  • Made in the USA
Cons
  • Heavy at 55 lb
  • Draws about 2.5 A idle outside search mode
  • Remote needed for lithium presets and most settings

The Magnum MS family

Every Magnum MS model we rank, smallest first. Ratings compare each against its own size.

ModelContinuousRatingPrice
Magnum Energy MS20122,000 W3.1/5$2,110.43
Magnum Energy MS2812 (this one)2,800 W3.5/5-

How it scores

The rating comes from 6 measured or published factors, each scored 0-100 against fixed reference points for its size. How we rank explains each one.

Specifications

Model numberMS2812
Output
TypePure sine wave inverter-charger
Continuous power2,800 W
Surge power3,900 W for 5 s
DC input range9 to 16.8 V
Idle draw2.5 A (30 W)
Power-saving draw0.7 A
Peak efficiency90%
Connections
AC outlets0
GFCI outletsNo
Hardwire terminalYes
USB portsNone
Transfer switchYes
Charger125 A
Lithium charge profileYes
Parallel unitsNo
Control and build
RemoteOptional extra
AppOptional add-on
DisplayNo
Safety listingETL listed to UL/cUL 458, CSA C22.2 No. 107.1-01; meets KKK-A-1822E
Coolingfan
Dimensions13.75 x 12.65 x 8.0 in (34.9 x 32.1 x 20.3 cm)
Weight55 lb
Warranty3 years

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